This applet demonstrates how to track the users that are currently
in a database. Instead of using the .ldb file, which only names the
machines that are logged in, it inserts the windows login of each user
along with a date/timestamp of their login, into a table. Upon the
closing of a hidden form (i.e., when the app exits), it then deletes
that record. This way only those who are actively logged in, or who
didn't exit cleanly their last time in, are listed in the table.
Uses one Win32 API call